The apolipoprotein E ϵ4 allele is not associated with psychiatric symptoms or extrapyramidal signs in probable Alzheimer's disease

Abstract

The objective of our study was to examine the relationship between the presence of the apolipoprotein E (apo E) ϵ4 allele, psychiatric symptoms, and extrapyramidal signs (EPS) in probable Alzheimer's disease(AD). The apo E ϵ4 allele modifies the risk and age at onset of AD. However, it still needs to be determined whether it is a marker for specific clinical subgroups. The frequency of clinical signs and symptoms was examined in 194 AD patients with the apo E ϵ3/3 (N = 79), ϵ3/4 (N = 96), andϵ4/4 (N = 19) genotypes participating in a longitudinal study of dementia. Each patient was assessed with semistructured psychiatric and neurologic examinations. Patients with the ϵ4/4 genotype had an earlier age at onset of dementia (p = 0.03). However, no individual psychiatric symptom or neurologic sign was associated with the presence of the apo E ϵ4 allele, including major depression (odds ratio [OR], 1.14; CI, 0.50 to 2.45; p = 0.78), psychosis (e.g., delusions and hallucinations) (OR, 0.66, CI, 0.35 to 1.25; p= 0.20), and EPS (in neuroleptic-free patients) (OR, 0.82, CI, 0.45 to 1.49; p = 0.52), after controlling by age at onset, duration of the symptoms, education, and severity of dementia. The presence of the apo E ϵ4 allele has limited utility in the characterization of neurologic and psychiatric subgroups in probable AD patients. The apo E ϵ4/4 genotype appears to be related to age at onset of AD, consistent with previous findings.